A popular Iranian singer who publicly defied regime censorship by releasing pro-opposition songs on the internet has been sentenced to a year in jail.

Arya Aramnejad, 28, a musician from Iran's northern city of Babol, fell foul of the authorities after singing political songs in condemnation of the regime's crackdown against the Green movement.

Aramnejad – whose works are banned inside Iran – initially released two songs in support of the movement during the campaign period before the country's disputed presidential elections in 2009.

In the unrest following the elections, which saw dozens of protesters killed and hundreds arrested, Aramnejad released music that particularly infuriated officials and led to his arrest.

The songs were about the Ashura protests in December 2009 , when the Green movement exploited a religious rally in Iran's Shia Islam calender to express their anger to a regime which describes itself as Islamic and says it abides by Islamic principals.

Shortly after the protests, Aramnejad released a song called Ali Barkhiz (Wake-up Ali, or Rise Ali), which spoke out against the violent crackdown against the opposition. Hundreds of protesters were arrested during Ashura protests and riot police was reported to have opened fire to contain the protesters. A video posted on YouTube showing what appears to be a security truck running over protesters and dead bodies sparked an outcry.

The "Ali" in Ali Barkhiz had a double-meaning, referring both to the first name of the Iranian supreme leader – calling upon him to wake up and see reality – or Imam Ali, a cousin of the prophet Muhammad and revered among Shia Muslims as a symbol of justice, calling upon him to rise and uproot injustice.

Security forces arrested Aramnejad for the first time in February 2010 after his song attracted a great deal of attention. He spent 45 days in solitary confinement before being allowed to contact his family. He was later sentenced to six months, a term he served from November 2011 until recently, when he was allowed out of prison for the Persian new year.

While in jail, he has been subjected to mistreatment and torture – including sexual humiliation – his friends say. He has never been granted legal representation.

A friend of Aramnejad who spoke to the Guardian on condition of anonymity, said: "Arya has been recently informed that he has been given a one-year jail sentence for his other songs released since 2010."

He's been accused of acting against national security and spreading propaganda against the regime, the friend said.